1. Field of the Invention
Embodiments of the present invention generally relate to well production. More particularly, the invention relates to a valve for a velocity string.
2. Description of the Related Art
Wells typically include casing and production tubing. The casing is used to prevent the wellbore from collapsing, and the production tubing is used to convey wellbore fluid, such as natural gas or petroleum, to the surface of the well. The production tubing is suspended within the casing by a collar that connects the top of the production tubing to the top of the casing.
Over the life-span of the well, a gradual reduction in well pressure causes a corresponding reduction in the exit velocity of the wellbore fluid from the well through the production tubing. After the exit velocity drops below an acceptable level, production from the well is boosted by inserting a coil tubing velocity string within the production tubing. The coil tubing velocity string has a smaller diameter than a diameter of the production tubing and thus the coil tubing velocity string has a smaller fluid flow area. The smaller fluid flow area in the coil tubing velocity string will result in an increased fluid flow velocity.
Typically, the coil tubing velocity string is deployed into the live well with an end plugged for pressure control. After producing wellbore fluid through the coil tubing velocity string, it may be necessary to pull out the coil tubing velocity string from the production tubing. However, the well must be killed or a micro-type bridge plug must be set in the coil tubing velocity string to control the pressure prior to pulling the coil tubing velocity string from the production tubing. These pressure control techniques can be expensive or may cause damage to the well. Therefore, there is a need for a device that can be used with the coil tubing velocity string for pressure control that is cost-effective and minimizes damage to the well.